Using dconf, I was able to edit the "gtk-color-scheme" in org -> gnome -> desktop -> interface. Using this, I was able to edit the parameters for the theme in a way that suited me. Here they are, for reference:

I copied over my Radiance theme from /usr/share/themes and copied it to my ~/.themes directory, and edited the "gtkrc" file. However, the colors did not change properly. How exactly can I edit my "gtkrc" file properly?

I'm using this theme for Unity--I probably should have brought that up. So, I edit the GTK-3.0 rather than the GTK-2.0?
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Ryan McClureJul 31 '12 at 4:10

The file settings.ini located in the gtk-3 folder of the Radiance theme has this text: gtk-color-schema which I guess is what dconf changes.I'd just edit the gtk.css file directly instead of doing it through dconf. I have changed the settings.ini file before but never noticed anything changing but I don't use Unity nor Gnome Shell so the changes might not affect my desktop environment.
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Uri HerreraJul 31 '12 at 4:21

Editting that changed the theme for MOST applications, I'm a little confused as to why it didn't edit Nautilus or some other applications.
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Ryan McClureJul 31 '12 at 4:24

Where to get GTK themes
You can get GTK themes from, for example, xfce-look.org gnome-look.org deviantart.com
How do I install these themes?
You only need to untar those themes under ~/.themes, so first:
mkdir ~/.themes
and then:
cd ~/.themes
tar -zxvf theme-name-here.tar.gz or
tar -jxvf theme-name-here.tar.bz2
Make sure you check the readme for what engines the theme needs. You can most likely install them through your package manager, like:
apt-get install gtk2-engines-pixbuf or
apt-get install gtk2-engines-* or
emerge gtk2-engines-pixbuf
You should get the idea.
And to use them?
GTK2
Get gtk-theme-switch (note that there is also a version for GTK2) or gtk-chtheme. Then just fire 'em up and you should see a nice list of all styles. Just select the one you want to use and click Apply. You can also use LXAppearance to change the gtk-themes.
This shows you how to edit GTK settings without any extra application installed.
Install the GTK theme as shown above (extract theme to ~/.themes and icon set to ~/.icons).
Create or edit the ~/.gtkrc-2.0 file. In that file input parameters such as the following:
#sets the font
gtk-font-name = "sans 8"
#sets the theme
gtk-theme-name = "Clearlooks Crystal 1.1"
#sets the icon theme
gtk-icon-theme-name = "CrystalClear-GNOME-1.0.0"
#shows only icons in the toolbar
gtk-toolbar-style = GTK_TOOLBAR_ICONS
#shows small icons in the toolbar
gtk-toolbar-icon-size = GTK_ICON_SIZE_SMALL_TOOLBAR
#sets the background color in Rox back to white because some GTK themes set it to light gray
style "rox" = "default"
{
bg[NORMAL] = "#ffffff"
bg[ACTIVE] = "#ffffff"
}
widget_class "*Collection*" style "rox"
Resources: http://www.gtk.org/api/2.6/gtk/GtkSettings.html
You can also use a different GTK theme, icon theme and fonts for specific GTK applications. If you just want to change the GTK theme, run your application with the following command:
GTK2_RC_FILES=/path/to/your/theme/gtkrc your_application
If you like to set a custom icon theme and font, create an empty file wherever you find convenient and call it whatever you want (for example, ~/.themes/custom.gtkrc). Then fill it with your different settings:
gtk-font-name = "sans 7"
gtk-theme-name = "niroki"
gtk-icon-theme-name = "SimplyGrey"
Now run the application with the following command:
GTK2_RC_FILES=/path/to/your/custom.gtkrc your_application
Add the command in your menu or launcher and enjoy.
GTK3
To use GTK3 themes, edit (or create) the ~/.config/gtk-3.0/settings.ini file. Specify the theme you want with the gtk-theme-name parameter. For example, if you want to use the Adwaita theme, your settings.ini file should looks like :
[settings]
gtk-theme-name = mindaryan
That's it.

Most of the time, it's not too hard to change the theme back or removed whatever software you've installed. If you've been infected with malware, then reinstalling from scratch is a very sound approach. But most of the time, if you've hurt your system's performance and have a good idea of what changes you made, you can just undo them.
–
Eliah KaganJul 31 '12 at 16:02